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8 results on '"Yingda Zhai"'

1. Pressure reduction mechanism and effect of working face passing through abandoned roadway by roof presplit

Author

Yunlou Du, Guorui Feng, Yujiang Zhang, Xihong Zhang, Yingda Zhai, and Jinwen Bai

Subjects
abandoned roadway, residual coal mining, roof presplit, vertical displacement, vertical stress, working resistance, Technology, Science
Abstract

Abstract Due to the existence of abandoned roadways in the thick coal seam, the ground pressure would increase greatly due to the roof advanced breaking when the working face passed through the affected area of abandoned roadways. In order to solve this problem, a solution for roof presplit in the abandoned roadway was proposed. Based on the mining and geological conditions of Huasheng Hufeng coal mine, the roof vertical stress and vertical displacement with different roof presplit distance were analyzed by using FLAC3D numerical software. The research results indicated that the roof vertical stress and vertical displacement could be reduced effectively by roof presplit. When the roof presplit distance was 15 m, the maximum vertical stress and the maximum vertical displacement were both minimum. The maximum vertical stress was reduced by 14.55% and the maximum vertical displacement was reduced by 37.51% after roof presplit. The reasonable roof presplit distance of the working face was determined to be about 15 m by combining theoretical and numerical analysis. The engineering application results indicated that the maximum working resistance of the hydraulic support was reduced by 35.86% after roof presplit, and the engineering effect was good. The research results can provide technical guidance and theoretical support for the same type mines.

Published
2020
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7. Network Externality and Trust in AgentBased Social Commerce.

Author

Jingqiao Tao, Mingliang Jiang, and Yingda Zhai

Subjects
COMMUNITY involvement, ECONOMICS, SOCIAL influence, SOCIAL network analysis, BENEVOLENCE
Abstract

The social commerce platform engages users in an agent-led network, leveraging local ties and communal trust. Agents are neighborhood influencers facilitating user referral, community engagement, and product marketing. We study the economic value of the agents to the platform based on their native endowed network externality and the trust formulated from the interaction with the users. Using detailed performance and referral data from a leading social commerce platform in Indonesia, we find that (1) agents with a higher level of endowed network externality outperform the ones with a lower level; (2) a more trustworthy and, surprisingly, less connected agent produces higher community sales; and (3) user’s perceived benevolence of the agent positively moderates the referral effect. The results suggest that the platform faces a trade-off between capitalizing on agents’ social connections and nurturing community trust. [ABSTRACT FROM AUTHOR]

Published
2023

8. Selling Tickets as Options: Airline Price Dispersion with Limited Seat Capacity

Author

Yingda Zhai

Subjects
Microeconomics, Capacity limit, Price dispersion, Business, Price discrimination, Sequential screening, Monopoly, Empirical evidence, Constraint (mathematics), Original data
Abstract

This paper develops a theoretical model for the optimal design of airfare as options under capacity constraint to study the price dispersion in U.S airline industry. Monopoly seller uses a menu of refund contracts to sequentially screen heterogeneous travelers who purchase the tickets before travel uncertainty is fully resolved. Airline finds it optimal to sell fully refundable fares to high-value customer when capacity is limited and to sell partially refundable fare when seats are abundant. The change of capacity accounts for the distinct jumps of non-refundable fare and the variation of refundable fare over booking periods. The model predicts that the price dispersion might fluctuate and then diminish as the number of available seat shrinks. An original data, which contains both high-frequent price and seat availability information for differentiated fares, provides strong empirical evidence that the price gap experiences step-wise drops before diminishing as departure date nears.

Published
2015
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